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<FONT color="green">001</FONT>    package org.hackystat.dailyprojectdata.frontsidecache;<a name="line.1"></a>
<FONT color="green">002</FONT>    <a name="line.2"></a>
<FONT color="green">003</FONT>    import java.util.HashMap;<a name="line.3"></a>
<FONT color="green">004</FONT>    import java.util.Map;<a name="line.4"></a>
<FONT color="green">005</FONT>    <a name="line.5"></a>
<FONT color="green">006</FONT>    import org.hackystat.dailyprojectdata.server.Server;<a name="line.6"></a>
<FONT color="green">007</FONT>    import org.hackystat.utilities.stacktrace.StackTrace;<a name="line.7"></a>
<FONT color="green">008</FONT>    import org.hackystat.utilities.uricache.UriCache;<a name="line.8"></a>
<FONT color="green">009</FONT>    <a name="line.9"></a>
<FONT color="green">010</FONT>    /**<a name="line.10"></a>
<FONT color="green">011</FONT>     * A cache for successfully DPD instances.  It is a "front side" cache, in the sense<a name="line.11"></a>
<FONT color="green">012</FONT>     * that it faces the clients, as opposed to the caches associated with the SensorDataClient<a name="line.12"></a>
<FONT color="green">013</FONT>     * instances, which are "back side" in that they cache sensor data instances.  While the<a name="line.13"></a>
<FONT color="green">014</FONT>     * "back side" caches avoid calls to the lower-level sensorbase, this front-side cache <a name="line.14"></a>
<FONT color="green">015</FONT>     * avoids the overhead of DPD computation itself.<a name="line.15"></a>
<FONT color="green">016</FONT>     * &lt;p&gt;<a name="line.16"></a>
<FONT color="green">017</FONT>     * The front side cache is organized as follows.  Each DPD instance is associated with a <a name="line.17"></a>
<FONT color="green">018</FONT>     * project and a project owner. The FrontSideCache is implemented as a collection of<a name="line.18"></a>
<FONT color="green">019</FONT>     * UriCaches, one for each project owner.  When a client adds data to the FrontSideCache, it<a name="line.19"></a>
<FONT color="green">020</FONT>     * must supply the project owner (which is used to figure out which UriCache to use),<a name="line.20"></a>
<FONT color="green">021</FONT>     * the URI of the DPD request (which is the key), and the string representation of the <a name="line.21"></a>
<FONT color="green">022</FONT>     * DPD (which is the value).  <a name="line.22"></a>
<FONT color="green">023</FONT>     * &lt;p&gt;<a name="line.23"></a>
<FONT color="green">024</FONT>     * The FrontSideCache currently has hard-coded maxLife of 1000 hours and each UriCache has<a name="line.24"></a>
<FONT color="green">025</FONT>     * a capacity of 1M instances. We could set these via ServerProperties values if necessary. <a name="line.25"></a>
<FONT color="green">026</FONT>     * &lt;p&gt;<a name="line.26"></a>
<FONT color="green">027</FONT>     * There is one important component missing from the FrontSideCache, and that is access<a name="line.27"></a>
<FONT color="green">028</FONT>     * control.  The FrontSideCache does not check to see if the client checking the cache has <a name="line.28"></a>
<FONT color="green">029</FONT>     * the right to retrieve the cached data.  To perform access control, you should use <a name="line.29"></a>
<FONT color="green">030</FONT>     * the SensorDataClient.inProject(owner, project) method, which checks to see if the <a name="line.30"></a>
<FONT color="green">031</FONT>     * user associated with the SensorDataClient instance has the right to access information<a name="line.31"></a>
<FONT color="green">032</FONT>     * about the project identified by the passed owner/project pair.  To see how this <a name="line.32"></a>
<FONT color="green">033</FONT>     * works, here is some example get code, which checks the cache but only returns the <a name="line.33"></a>
<FONT color="green">034</FONT>     * DPD instance if the calling user is in the project:<a name="line.34"></a>
<FONT color="green">035</FONT>     * &lt;pre&gt;<a name="line.35"></a>
<FONT color="green">036</FONT>     * String cachedDpd = this.server.getFrontSideCache().get(uriUser, uriString);<a name="line.36"></a>
<FONT color="green">037</FONT>     * if (cachedDpd != null &amp;&amp; client.inProject(authUser, project)) {<a name="line.37"></a>
<FONT color="green">038</FONT>     *   return super.getStringRepresentation(cachedDpd);<a name="line.38"></a>
<FONT color="green">039</FONT>     * }<a name="line.39"></a>
<FONT color="green">040</FONT>     * &lt;/pre&gt;<a name="line.40"></a>
<FONT color="green">041</FONT>     *  <a name="line.41"></a>
<FONT color="green">042</FONT>     * @author Philip Johnson<a name="line.42"></a>
<FONT color="green">043</FONT>     *<a name="line.43"></a>
<FONT color="green">044</FONT>     */<a name="line.44"></a>
<FONT color="green">045</FONT>    public class FrontSideCache {<a name="line.45"></a>
<FONT color="green">046</FONT>      <a name="line.46"></a>
<FONT color="green">047</FONT>      /** The .hackystat subdirectory containing these cache instances. */ <a name="line.47"></a>
<FONT color="green">048</FONT>      private String subDir = "dailyprojectdata/frontsidecache";<a name="line.48"></a>
<FONT color="green">049</FONT>      <a name="line.49"></a>
<FONT color="green">050</FONT>      /** The number of hours that a cached DPD instance stays in the cache before being deleted. */<a name="line.50"></a>
<FONT color="green">051</FONT>      private double maxLife = 1000;<a name="line.51"></a>
<FONT color="green">052</FONT>    <a name="line.52"></a>
<FONT color="green">053</FONT>      /** The total capacity of this cache. */<a name="line.53"></a>
<FONT color="green">054</FONT>      private long capacity = 1000000L;<a name="line.54"></a>
<FONT color="green">055</FONT>      <a name="line.55"></a>
<FONT color="green">056</FONT>      /** Maps user names to their associated UriCache instance. */<a name="line.56"></a>
<FONT color="green">057</FONT>      private Map&lt;String, UriCache&gt; user2cache = new HashMap&lt;String, UriCache&gt;();<a name="line.57"></a>
<FONT color="green">058</FONT>      <a name="line.58"></a>
<FONT color="green">059</FONT>      /** The server that holds this FrontSideCache. */<a name="line.59"></a>
<FONT color="green">060</FONT>      private Server server = null;<a name="line.60"></a>
<FONT color="green">061</FONT>      <a name="line.61"></a>
<FONT color="green">062</FONT>      /** <a name="line.62"></a>
<FONT color="green">063</FONT>       * Creates a new front-side cache, which stores the DPD instances recently created.<a name="line.63"></a>
<FONT color="green">064</FONT>       * There should be only one of these created for a given DPD server.  Note that <a name="line.64"></a>
<FONT color="green">065</FONT>       * this assumes that only one DPD service is running on a given file system.  <a name="line.65"></a>
<FONT color="green">066</FONT>       * @param server The DPD server associated with this cache. <a name="line.66"></a>
<FONT color="green">067</FONT>       */<a name="line.67"></a>
<FONT color="green">068</FONT>      public FrontSideCache(Server server) { <a name="line.68"></a>
<FONT color="green">069</FONT>        this.server = server;<a name="line.69"></a>
<FONT color="green">070</FONT>      }<a name="line.70"></a>
<FONT color="green">071</FONT>      <a name="line.71"></a>
<FONT color="green">072</FONT>      /**<a name="line.72"></a>
<FONT color="green">073</FONT>       * Adds a (user, dpd) pair to this front-side cache. <a name="line.73"></a>
<FONT color="green">074</FONT>       * The associated UriCache for this user is created if it does not already exist.<a name="line.74"></a>
<FONT color="green">075</FONT>       * Does nothing if frontsidecaching is disabled. <a name="line.75"></a>
<FONT color="green">076</FONT>       * @param user The user who is the owner of the project associated with this DPD.<a name="line.76"></a>
<FONT color="green">077</FONT>       * @param project The name of the project.<a name="line.77"></a>
<FONT color="green">078</FONT>       * @param uri The URL naming this DPD, as a string. <a name="line.78"></a>
<FONT color="green">079</FONT>       * @param dpdRepresentation A string representing the DPD instance. <a name="line.79"></a>
<FONT color="green">080</FONT>       */<a name="line.80"></a>
<FONT color="green">081</FONT>      public void put(String user, String project, String uri, String dpdRepresentation) {<a name="line.81"></a>
<FONT color="green">082</FONT>        if (isDisabled()) {<a name="line.82"></a>
<FONT color="green">083</FONT>          return;<a name="line.83"></a>
<FONT color="green">084</FONT>        }<a name="line.84"></a>
<FONT color="green">085</FONT>        try {<a name="line.85"></a>
<FONT color="green">086</FONT>          UriCache uriCache = getCache(user);<a name="line.86"></a>
<FONT color="green">087</FONT>          uriCache.putInGroup(uri, project, dpdRepresentation);<a name="line.87"></a>
<FONT color="green">088</FONT>        }<a name="line.88"></a>
<FONT color="green">089</FONT>        catch (Exception e) {<a name="line.89"></a>
<FONT color="green">090</FONT>          this.server.getLogger().warning("Error during DPD front-side cache add: " +<a name="line.90"></a>
<FONT color="green">091</FONT>              StackTrace.toString(e));<a name="line.91"></a>
<FONT color="green">092</FONT>        }<a name="line.92"></a>
<FONT color="green">093</FONT>      }<a name="line.93"></a>
<FONT color="green">094</FONT>      <a name="line.94"></a>
<FONT color="green">095</FONT>      /**<a name="line.95"></a>
<FONT color="green">096</FONT>       * Returns the string representation of the DPD associated with the DPD owner and the <a name="line.96"></a>
<FONT color="green">097</FONT>       * URI, or null if not in the cache. <a name="line.97"></a>
<FONT color="green">098</FONT>       * @param user The user who is the owner of the Project associated with this DPD.<a name="line.98"></a>
<FONT color="green">099</FONT>       * @param uri The URI naming this DPD. <a name="line.99"></a>
<FONT color="green">100</FONT>       * @param project The project associated with this URI.<a name="line.100"></a>
<FONT color="green">101</FONT>       * @return The string representation of the DPD, or null. <a name="line.101"></a>
<FONT color="green">102</FONT>       */<a name="line.102"></a>
<FONT color="green">103</FONT>      public String get(String user, String project, String uri) {<a name="line.103"></a>
<FONT color="green">104</FONT>        if (isDisabled()) {<a name="line.104"></a>
<FONT color="green">105</FONT>          return null;<a name="line.105"></a>
<FONT color="green">106</FONT>        }<a name="line.106"></a>
<FONT color="green">107</FONT>        UriCache uriCache = getCache(user);<a name="line.107"></a>
<FONT color="green">108</FONT>        return (String)uriCache.getFromGroup(uri, project);<a name="line.108"></a>
<FONT color="green">109</FONT>      }<a name="line.109"></a>
<FONT color="green">110</FONT>      <a name="line.110"></a>
<FONT color="green">111</FONT>      /**<a name="line.111"></a>
<FONT color="green">112</FONT>       * Clears the cache associated with user. Instantiates one if not available so that <a name="line.112"></a>
<FONT color="green">113</FONT>       * any persistent cache that has not yet been read into memory is cleared.<a name="line.113"></a>
<FONT color="green">114</FONT>       * @param user The user whose cache is to be cleared.<a name="line.114"></a>
<FONT color="green">115</FONT>       */<a name="line.115"></a>
<FONT color="green">116</FONT>      public void clear(String user) {<a name="line.116"></a>
<FONT color="green">117</FONT>        if (isDisabled()) {<a name="line.117"></a>
<FONT color="green">118</FONT>          return;<a name="line.118"></a>
<FONT color="green">119</FONT>        }<a name="line.119"></a>
<FONT color="green">120</FONT>        try {<a name="line.120"></a>
<FONT color="green">121</FONT>          UriCache uriCache = getCache(user);<a name="line.121"></a>
<FONT color="green">122</FONT>          uriCache.clear();<a name="line.122"></a>
<FONT color="green">123</FONT>        }<a name="line.123"></a>
<FONT color="green">124</FONT>        catch (Exception e) {<a name="line.124"></a>
<FONT color="green">125</FONT>          this.server.getLogger().warning("Error during DPD front-side cache clear: " +<a name="line.125"></a>
<FONT color="green">126</FONT>              StackTrace.toString(e));<a name="line.126"></a>
<FONT color="green">127</FONT>        }<a name="line.127"></a>
<FONT color="green">128</FONT>      }<a name="line.128"></a>
<FONT color="green">129</FONT>    <a name="line.129"></a>
<FONT color="green">130</FONT>      /**<a name="line.130"></a>
<FONT color="green">131</FONT>       * Clears all of the cached DPD instances associated with this project and user. <a name="line.131"></a>
<FONT color="green">132</FONT>       * @param user The user. <a name="line.132"></a>
<FONT color="green">133</FONT>       * @param project The project. <a name="line.133"></a>
<FONT color="green">134</FONT>       */<a name="line.134"></a>
<FONT color="green">135</FONT>      public void clear(String user, String project) {<a name="line.135"></a>
<FONT color="green">136</FONT>        if (isDisabled()) {<a name="line.136"></a>
<FONT color="green">137</FONT>          return;<a name="line.137"></a>
<FONT color="green">138</FONT>        }<a name="line.138"></a>
<FONT color="green">139</FONT>        try {<a name="line.139"></a>
<FONT color="green">140</FONT>          UriCache uriCache = getCache(user);<a name="line.140"></a>
<FONT color="green">141</FONT>          uriCache.clearGroup(project);<a name="line.141"></a>
<FONT color="green">142</FONT>        }<a name="line.142"></a>
<FONT color="green">143</FONT>        catch (Exception e) {<a name="line.143"></a>
<FONT color="green">144</FONT>          this.server.getLogger().warning("Error during DPD front-side cache clear: " +<a name="line.144"></a>
<FONT color="green">145</FONT>              StackTrace.toString(e));<a name="line.145"></a>
<FONT color="green">146</FONT>        }<a name="line.146"></a>
<FONT color="green">147</FONT>      }<a name="line.147"></a>
<FONT color="green">148</FONT>      <a name="line.148"></a>
<FONT color="green">149</FONT>      <a name="line.149"></a>
<FONT color="green">150</FONT>      /**<a name="line.150"></a>
<FONT color="green">151</FONT>       * Returns true if frontsidecaching is disabled.<a name="line.151"></a>
<FONT color="green">152</FONT>       * @return True if disabled.<a name="line.152"></a>
<FONT color="green">153</FONT>       */<a name="line.153"></a>
<FONT color="green">154</FONT>      private boolean isDisabled() {<a name="line.154"></a>
<FONT color="green">155</FONT>        return !this.server.getServerProperties().isFrontSideCacheEnabled();<a name="line.155"></a>
<FONT color="green">156</FONT>      }<a name="line.156"></a>
<FONT color="green">157</FONT>    <a name="line.157"></a>
<FONT color="green">158</FONT>      /**<a name="line.158"></a>
<FONT color="green">159</FONT>       * Gets the UriCache associated with this project owner from the in-memory map.<a name="line.159"></a>
<FONT color="green">160</FONT>       * Instantiates it if necessary.<a name="line.160"></a>
<FONT color="green">161</FONT>       * @param user The user email (project owner) associated with this UriCache.<a name="line.161"></a>
<FONT color="green">162</FONT>       * @return A UriCache instance for this user. <a name="line.162"></a>
<FONT color="green">163</FONT>       */<a name="line.163"></a>
<FONT color="green">164</FONT>      private UriCache getCache(String user) {<a name="line.164"></a>
<FONT color="green">165</FONT>        UriCache uriCache = user2cache.get(user);<a name="line.165"></a>
<FONT color="green">166</FONT>        if (uriCache == null) {<a name="line.166"></a>
<FONT color="green">167</FONT>          uriCache = new UriCache(user, subDir, maxLife, capacity);<a name="line.167"></a>
<FONT color="green">168</FONT>          user2cache.put(user, uriCache);<a name="line.168"></a>
<FONT color="green">169</FONT>        }<a name="line.169"></a>
<FONT color="green">170</FONT>        return uriCache;<a name="line.170"></a>
<FONT color="green">171</FONT>      }<a name="line.171"></a>
<FONT color="green">172</FONT>    <a name="line.172"></a>
<FONT color="green">173</FONT>    }<a name="line.173"></a>




























































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